Cataracts, what are they?

Cataracts, what are they?

Our Ophthalmic team at Bridge Referrals have created a Cataracts blog providing valuable information and support to give to pet owners facing this issue.

What is a cataract? 

A cataract is an abnormal opacity or clouding of the lens or lens capsule which can give the eye a white appearance. They are caused by a change in the structure of the lens material.

Normally the lens is a transparent structure which enables light to pass to the back of the eye to form an image on the retina. When a cataract develops light can no longer pass through the lens and vision is reduced.  Cataracts usually get worse over time and are a common cause of blindness in dogs and cats. 

What causes cataracts?

There are many different conditions that can cause a cataract to develop.  

Inherited cataracts

In certain breeds of animals cataracts are known to be inherited.  Inherited cataracts can develop early in life (congenital) or later on in life (late onset) depending on the gene that is affected.

The British Veterinary Association (BVA), Kennel Club (KC) and the International Sheep Dog Society (ISDS) run a health scheme to identify inherited eye conditions (including cataracts) in dogs to reduce the incidence of disease.  

https://www.bva.co.uk/canine-health-schemes/eye-scheme/

Traumatic cataracts

These occur following trauma to the eye. A cataract can develop when the lens is injured with a penetrating object e.g. a thorn or stick, or can develop following a concussive injury with blunt trauma e.g. getting hit in the eye with a hard ball. If the injury is treated promptly, in some cases the progression of the cataract can be delayed but if there is significant damage to the intraocular structures a cataract can develop quickly.

Diabetic cataracts

This type of cataract rapidly progresses and affected dogs can become very disoriented and distressed. The lens absorbs fluid because of the raised blood glucose levels in diabetic patients. The lens then swells which changes the structure of the lens material and a cataract is formed. It is important that cataracts are assessed early on in diabetic patients because as the lens swells there is a high risk of lens capsule rupture which can cause uveitis and a painful eye.

Senile cataracts

This type of cataract is common. As we age our lens becomes more dense and the lens fibres degenerate causing a cataract. Senile cataracts often develop slowly causing a gradual loss of vision. Often owners are more likely to detect a visual disturbance when both eyes become affected.

Secondary cataracts

Cataracts can develop secondary to other conditions inside the eye including uveitis (intraocular inflammation), glaucoma (high intraocular pressure) and retinal disease. Controlling the primary intraocular conditions (where possible) can prevent or delay cataract development.

What are the symptoms of cataracts you might see?

The signs of cataracts developing are not always as obvious as you might expect, especially if they develop slowly or over a long period. You may notice:

• A cloudiness or grey tinge in your dog or cat’s eye
• Change in vision – these can be subtle changes (missing steps, reluctant to use stairs, reluctance to walk in new areas) because most dogs are very good at adapting by using their sense of smell and hearing
• Redness to the white part of the eye (sclera) – as cataracts develop they can cause inflammation in the eye
• Pain – cataracts aren’t painful but some of the underlying conditions and secondary complications are (such as uveitis or glaucoma)

What treatment is available?

The only treatment available for cataracts is surgical removal of the lens using a procedure called phacoemulsification. The aim of surgery is to remove the cataract and replace the lens with an artificial lens to restore vision. This is the same procedure used in human cataract surgery but we are usually awake during the procedure, surgery is performed under general anaesthesia in dogs and cats.

 

If surgery is not an option, medically managing the cataract won’t restore vision but helps to control lens induced uveitis which can be painful and if not controlled can progress to loss of the eye.

Early cataract assessment

Early cataract assessment is encouraged to optimise treatment. If surgery is performed as soon as vision affects the patients quality of life this reduces the risk of secondary complications, especially in young and diabetic patients where cataracts can progress quickly. Therefore assessing cataracts early and monitoring them as they develop is important.

Bridge Referrals offers cataract assessments with no commitment to surgery. If surgery is elected we offer a Fixed Fee price which includes the initial cataract assessment, surgery, and one month of postoperative examinations and medication. If you would like to know more about this service please contact us.

If you would like to arrange a cataract assessment please speak to your primary care vet to arrange a referral with us so that we have all your pets clinical history.